"If he didn't like it he could send it back and not be charged for that month." In this type of service that garuntee could come and bite you one month with a large amount of returns to which you're paying the shipping on. -Insta bankruptcy- so don't make those promises right off the bat until you're on a good run and know costs, avg return rate, profit levels/have investment backing/etc so that one slip up wouldn't result in a the end of the business.
My other issue in this is vagueness of 'favorite things' and 'tastes'. You can only have so many variants each month, 10 gifts that you've bought wholesale amounts of and will have your system sort who should be getting what that month. Going overboard with trying to pick the perfect gift for every single individual isn't scalable and wouldn't attract high profits since you wouldn't be purchasing in large quantities.
Other than that, I think it's a good idea. Tough part will be figuring out the price point so that you're distributing high quality gifts at a price that someone is more than willing to pay every month.